In considering a discrimination claim a tribunal will generally go through 2 stages: the first stage is to ensure that the claimant establishes facts from which in the absence of an adequate explanation it can be concluded that unlawful discrimination for which the respondent is responsible has taken place. Thus, the employee must make out a 'prima facie' case. If but only if the employee achieves that the second, subsequent, stage is engaged (see Appiah & Anor v Bishop Douglass Roman Catholic High School CA 2007 IRLR 264). The burden of proof then shifts to the employer to demonstrate if he can, on the balance of probabilities, that there was an adequate "non-discrimination" explanation for what took place. If he fails to demonstrate this then the tribunal is required to assume that he is "guilty".
This test is encapsulated by statue see: Sex Discrimination (Indirect Discrimination and Burden of Proof) Regulations 2001, SI 2001/2660 inserting s.63A into the Sex Discrimination Act 1975.
The 'reverse burden of proof' applies to cases of direct discrimination on grounds of colour (as well as on grounds of race, national or ethnic origin) see Race Relations Act 1976 (Amendment) Regulations 2003 SI 2003/1626 reg 41 (nserting a new s.54A into the Race Relations Act 1976 effective from 19th July 2003):
2) Where, on the hearing of the complaint, the complainant proves facts from which the tribunal could, apart from this section, conclude in the absence of an adequate explanation that the respondent -
(a) has committed such an act of discrimination or harassment against the complainant, or
(b) is by virtue of section 32 or 33 to be treated as having committed such an act of discrimination or harassment against the complainant,
the tribunal shall uphold the complaint unless the respondent proves that he did not commit or, as the case may be, is not to be treated as having committed, that act.".
A new development however, was the EAT's recent conclusion on the burden of proof in cases where the direct race discrimination was on grounds of colour. The employment tribunal had directed itself that the "reverse burden of proof" in Race Relations Act 1976 sec 54A applied to discrimination on grounds of race, national or ethnic origin but not to discrimination on grounds of colour until the contrapuntal case of Milton Keynes General Hospital NHS Trust (1) Punchard (2) v Maruziva EAT - 09/10/2009